Oxybisphenylsulfonhydrazide



Patented May 8, 1!?51 UNITED STATES PATEN T OFFICE OXYBISPHENYLSULFONHYDRAZIDE Dwight L: Schoene, Woodbridge, 'Conn., assignor to United States Rubber Compan N. Y., a corporation of New Jersey y, New York, I

- N Drawing. Application August 1; H50, Serial No. 177,115 I produced from hydrazine and p,p'-oxybis (benzene sulfonyl chloride) possesses the useful property of being unusually stable under normal storage conditions but upon heating undergoes a moderately rapid vdecomposition 'to produce nitrogen gas. Specifically, the invention lies in the discovery of p,p'-oxybis (benzene sulfonyl hydrazide) as a new and unique composition of matter.

' Certain organic compounds which decompose at moderately elevated temperatures to produce a gaseous decomposition'product have found use as blowing a ents in the manufacture of cellular rubber and cellular plastics. Not all compounds which producegas on heating are suitable for the purpose, however. For example, many compounds which decomposeon'heating may do'so explosively'a'nd are unsafe for use. Other chemicals decompose .,,.at temperatures either too highbr too'low'to'ineet the requirements of practical use. A very important requirement for blowing agents for cellular rubber, for example, is that the decomposition temperature be such that partial, but incomplete vulcanization of the rubber shall have occurred prior to the decomposition of the blowing agent. Otherwise, the rubber stock Will not have developed sufficient strength to retain the blowing gas or will have been cured to such an extent that proper expansion by this gas is not possible. Related to this requirement is the requirement that the blowing agent shall not have an adverse effect on the rate of vulcanization of the rubber compositionan effect which would seriously alter the desired cellular structure of the product. Another requirement of a superior blowing agent is that the blowing agent shall not produce discoloration of the product nor cause staining of coatings or other materials that come in contact with the blown product.

A further requirement is that the blowing agent will not produce odorous, toxic, or otherwise objectionable decomposition products in the sponge. Although a number of compounds have been proposed as non-discoloring blowing agents none of the materials that have been introduced is completely satisfactory.

It has now been found that p,p'-oxybis (benzene sulfonyl hydrazide) is an outstanding blow- 1 Claim. (c1. 260-556) However, the decomposition products odorous and the use 'of the materials is greatly rubber and tenure? plastics I The chemical possesses the properties required for this application to a degree that is unique and not found in other classes of blowing agents. Certain sulfonhydrazides such as methane sulfonyl hydrazide and benzene sulfonyl hydrazide decompose at suitable temperatures to produce gas and are capable of producing cellularplastics.

limited thereby. Naphthalene 2,7 disulfonyl hydrazide decomposes to give decomposition products having little odor but the material difficult to obtain in a" pure form and tends to 1 create discoloration in stocks in which it is placed;

U preparation of p,p'-bis (benzene sulfonyl hydrazide) for example, the" sulfonation'of biphenyl is a necessary step. This reaction involves the treatment of biphenyl with chlorosulfonic acid, and the formation of undesirable by-products is difficult to avoid. The formation of xenylene 2,2'sulfone 4,4 disulfonyl chloride, for example, is an undesirable side reaction when biphenyl is used. A further undesirable side reaction with biphenyl is the formation of biphenyl mono sulfonyl chloride. In contrast to the difiiculties attending the di-chloro-sulfonation of biphenyl, the reaction of chlorosulfonic acid with diphenyl ether produces the desired oxybis (benzene sulfonyl chloride) in good yield and the product is not contaminated with an undesirable sulfone as is the case with biphenyl. Furthermore, the product is not contaminated with a mono sulfonation product, sulfonation to the disulfonated product always taking place. The oxybis (benzene sulfonyl chloride) is isolated in a sufficiently pure state by a very simple process and is readily converted to the corresponding sulfonyl hydrazide as hereinafter described. The ether oxygen in the compound has a number of rather surprising eifects. It labilizes the para position 0 for easy sulfonation and prevents the formation of the undesirable cyclic by-products. It also improves solubility of the blowing agent in the rubber or plastic mix, especially in a plastisol (i. e., a mixture of particulate resin and a plastiing agent for the manufacture of both cellular 5; cizer therefor) and thus provides finer cell struc- H H HzNNS 100 s o nma,

and is most conveniently made by reacting diphenyl ether with chlorosulfonic acid in known manner to give p,p'-oxybis (benzene sulfrfonyl;

chloride), which can, if desired, be isolated or purified in any suitable manner and which is subsequently reacted with hydrazine to give the newcomp nd of y nv ion he a ti n wit hydr zin ca be e t dbysimmy com i el ng the, two. reactants at any suitable temperature, which can conveniently range from atmospheric or, room temperature (circa 20 C'.) to 100 C. The reaction is preferably carried out in an inert liquid medium such as water, ethanol, methanol, and dioxane. I prefer to employ a substantial molar excess of hydrazine in order to ensure complete c m tion of e .p'o ybi s (b z ne sulfonyl chloride) reactant. The excess of hydrazine iseasily separated from the product, h p od ct. beine nre nit tedand reco ere by filtration; the product can be freed from anyresidual hydrazine by simple water washing since hydrazine is readily solublein water whereas the product is much less water-soluble.

The reaction between p,p-oxybis (benzene sulfohyl chloride) and hydrazine is illustrated as follows:

i n H mums (MQQrOSOaNNHl 4e 213.01

It will be seen that complete reaction requires 2 mols of hydrazine per mol of p,p'-oxybis (benzene sulfonyl chloride). It is often preferred to carry out the reaction in the presence of a hydrogen chloride acceptor (an excess of hydrazine) which promotes the reaction in the desired direction by displacing the, equilibrium rightwardly in the above equation,

The use of aromatic sulfonyl hydrazides generally and of p,p'-oxybis (benzene sulfonyl chloride) specifically as blowing agents for organic plastic'materials is described and claimed in, the copehding application of Byron A. Hunter and Ruth L, Stander, Serial No. 176,084, filed uly-26, 1 50- Example p,p'-Oxybis (benzene sulfonyl hydrazide) was prepared by reacting p,p'-oxybis (benzene sulfonyl chloride) (Suter, J. Am. Chem. Soc. 53, 1112 (1931)) with four moles of hydrazine in the presenceof, ethyl alcohol as a reaction medium. The two reactants are simply brought together in, the presence of the, ethyl alcohol and allowed to stand, at room temperatureuntil reaction is substantially complete, After completion of the, reaction the solid P YQduQ Z was filtered oil and washed well with water, he crude product did not melt but decomposes with evolution of gas at, 135,-L40 C., compound may be recrystallized from water, whereupon the decomposition point is increased to 161 C, Analysis of the purified material gave sulfur 1.164% and nitrogen 16.30%. The values calculated for C12H14S205N4 are sulfur 17,78% and nitrogen 15.64%. The product was used withoutstanding success for blowing rubber and polyvinylchloride-plasticizer mixtures.

Having thus described my invention, what I claim and desire to protect bjy Letters Patent, is:

As a new chemical compflund, p,p'-oxybis (benzene sulfonyl hydrazide DWIGHT L. SCHOENE.

No references cited. 

